<ul>
    <li><a href="<?php echo base_url();?>trangchu"><span>Trang chủ</span></a></li>
    <?php if(isset($nganh)){?>
    <li><a href=""><span>Danh mục ngành</span></a>
        <ul>
        <?php foreach($nganh->result_array() as $rownganh):?>
            <li><a href="<?php echo site_url('nganh/hienthinganh/'.$rownganh['id'].'/'.ham_loc_dau($rownganh['ten_nganh']));?>"><span><?php echo $rownganh['ten_nganh'];?></span></a></li>
        <?php endforeach;?>
        </ul>
    </li>
    <li><a href="<?php echo site_url('gioithieu');?>"><span>Giới thiệu</span></a></li>
    <li><a href="<?php echo site_url('lienhe');?>"><span>Liên hệ</span></a></li>
    <?php }?>
</ul>
<form method="post" action="<?php echo site_url('timkiem/index');?>" id="timkiem">
    <input type="text" name = "keyword" id="text" size="25" />
    <input id="mit" type="submit" name="btnsearch" value="Tìm Kiếm"/>
</form>